Gripping means for doffing yarn packages

ABSTRACT

Yarn packages wound on tubes by ring spinning machinery are doffed by an arm which is lowered until a ring carried thereon encircles the tube end portion. The ring has a gap and the two free ring ends are positively moved toward each other across the gap to contract the ring to embrace the tube. A separate lever arm is connected to each ring free end. The two levers are disposed substantially parallel and are normally wedged apart to maintain the ring ends in spread condition to receive a tube. Electromagnetic drive means effect movement of the levers together to contract the ring and grip a tube end. After the arm is raised, the levers are spread to release the tube and a plate above the ring presses the tube quickly out of the ring.

United States Patent [191 Goldammer et al.

[451 June 4,1974

[ 1 GRIPPING MEANS FOR DOFFING YARN PACKAGES [75] Inventors: GeorgGoldammer, Friedrichshofen;

Eberhard Grimm, Ingolstadt; Emil Egli, Windisch, all of Switzerland [73]Assignee: Schubert & Salzer Maschinenfabrik Aktiengesellschaft,lngolstadt, Germany [22] Filed: Jan. 31, 1.972

[21] Appl. No.: 221,864

[30] Foreign Application Priority Data Feb. 5, 1971 Germany 2105344 [52]US. Cl 57/52, 294/67 BC [51] Int. Cl ..D01h 9/08 [58] Field of Search57/52, 53, 54; 242/41; 294/8722, 87.24, 67 BC [56] References CitedUNITED STATES PATENTS 1,463,479 7/1923 Miller 57/52 2,862,756 12/1958Larson 294/67 BC X 2,962,856 12/1960 Ingham, .Ir 57/52 3,053,561 9/1962Hamel 294/8722 3,307,340 3/1967 Nishii et al 57/53 3,398,522 8/1968Niederer 57/53 3,408,806 11/1968 Fess et al. 57/53 3,442,072 5/1969Gillono et a1. 57/53 3,566,597 3/1971 Para 57/53 3,633,959 1/1972MCCOIlOugh et al. 57/52 X FOREIGN PATENTS OR APPLICATIONS 1,012,78912/1965 Great Britain 57/53 Primary Examiner.lohn W. l-Iuckert AssistantExaminer-Charles Gorenstein Attorney, Agent, 0r'Firm-Robert W. Beach;Ms. R. M. Van Winkle 5 7 ABSTRACT Yarn packages wound on tubes by ringspinning machinery are doffed by an arm which is lowered until a ringcarried thereon encircles the tube end portion. The ring has a gap andthe two free ring ends are positively moved toward each other across thegap to contract the ring to embrace the tube. A separate lever arm isconnected to each ring free end. The two levers are disposedsubstantially parallel and are normally wedged apart to maintain thering ends in spread condition to receive a tube. Electromagnetic drivemeans effect movement of the levers together to contract the ring andgrip a tube end. After the arm is raised, the levers are spread torelease the tube and a plate above the ring presses the tube quickly outof the ring.

2 Claims, 4 Drawing Figures GRIPPING MEANS FOR DOFFING YARN PACKAGESBACKGROUND INVENTION 1. Field to which invention relates The inventionrelates more particularly to a gripping means for doffing .yarn packageson ring spinning and ring doublingtmachines, comprising an annulargripping or clamping element adapted to engage the core of the yarnpackage.

2. The prior art In accordance with a previous proposal an elastic,closed gripping ring was to be used for doffing yarn packages on ringspinning and ring doubling machines (hereinafter referred to as ringspinning machinery). This gripping ring was moved downwards onto the endof the package core and changed in size by pressure acting from above onthe ring so that the ring gripped the periphery of the core (see Britishpatent specification 1,012,789). The reliabilitypf operation of thisgripping ring, which was to be provided on a doffing arrangementtravelling uninterruptedly along the machine, was however insufficientbecause, owing to its necessarily very elastic or resilientconstruction, it was not possible to achieve a sufficiently positiveaction. In the case of such yarn package doffing devices, only fractionsof a second are available for engaging the core or tube and part of thistime is required, in case of pressure acting from above on the ring, forinitial stressing of the ring. The remaining time is not sufficient toreduce the size of the ring to such an extent that the core or tube isgrasped with sufficient force for doffing. A further disadvantage of thepreviously proposed gripping ring is that the bore of the ring must bemade very small and can only exceed the diameter of the end of the coreby a slight amount in order to allow the ring to be rapidly pressed onthe core or tube. The gripping ring can therefore only grasp the end ofthe tube when its diameter does not exceed the prescribed size and thespindle, on which the tube is mounted, is precisely vertical. If one ofthese conditions is not fulfilled, the core cannot enter the bore of thegripping ring.

In accordance with a still further prior proposal (see British patentspecification 1,012,789) for a gripping element, use was-to be made of-a band which surrounded the upper end of the core and was drawn tightby a force acting on the end of the band. However, it is found that theforce acting on the band is to a substantial extent taken up byovercoming friction and can only act with a certain time lag on thewhole end of the core, so that such a gripping element cannot properlyengage the end of the core in the time which is actually available.

SUMMARY OF INVENTION One aim of the present invention is to provide anannular gripping element which is engageable with the outer periphery ofthe core of a yarn package and which avoids the above-mentioneddisadvantages.

The present invention is a gripping or clamping device for doffing yarnpackages on ring spinning machinery comprising a gripping snap ringadapted to engage theouter surface of the core of such a yarn packageand means connected with ends of the ring at'opposite sides of the ringgap for applying force to the ring for changing its diameter. The meansfor applying the force can be adapted to exert either a tension or athrust force. In accordance with one particular embodiment of theinvention the gripping ring comprises a number of secondary rings. Inorder to engage the whole of the outer peripheral surface of the core,the gaps in these secondary rings are circumferentially offset from oneanother. In accordance with another embodiment of the invention theinterrupted ring comprises two ring segments and one end of each suchsegment is fixed at a stationary point. The two ends of the ringsadjacent to the gap in the ring can be moved in relation to each other.By simultaneous movement of the ends toward each other, an acceleratedcontraction of the ring is brought about. The gripping action of theinterrupted ring can be improved by making it of a flexible,non-elastic, band-like part which on its inner surface has an elasticcoating. In accordance with a further feature of the invention, asolenoid is used to produce the thrust or tension forces. The bore ofthe gripping ring is closed in an upward direction by a pressure platewhich can be moved vertically. This makes possible an acceleratedejection of the core or tube with the rest of the yarn package from thegripping ring.

LIST OF SEVERAL VIEWS OF DRAWINGS Further details of the invention willnow be described with reference to the accompanying drawings.

FIG. 1 is a diagrammatic bottom plan of a gripper arm showing the deviceof the invention.

FIG. 2 is a longitudinal section along the line II-II of FIG. 1.

FIG. 3 is a plan of a two-piece gripping ring.-

FIG. 4 is an exploded top perspective of a gripping element made up ofseveral secondary rings.

DESCRIPTION OF PREFERRED EMBODIMENTS The gripping arm shown in FIGS. 1and 2 is part of a doffing device which can travel along ring spinningmachinery, that is to say a ring spinning or ring doubling frame. Inmany respects the doffing device can be of conventional construction, asdescribed for instance in the above-mentioned British patentspecification 1,012,789. The gripper arm 1 is actuated by a drive via athrust rod 10. The drive can be as described in the same British patentspecification and is therefore not described in detail.

In the head, which is provided with a centering plate 11, of thegripping arm I, a gripping or clamping ring 2 constituting a gripping orclamping element is mounted so as to be capable of moving. In accordancewith the invention the gripping ring is an interrupted ring with ends 21and 22 adjacent to the interruption or gap. The gripping ring 2 includesa flexible nonelastic part 20 in the form of a band and an elasticlining or coating 20 fixed on the part 20. While the flexible part 20 ispreferably in the form of a strip string, the elastic part 20' can bemade of rubber, plastics material or another material increasingfrictional engagement with the package core. If rubber is selected as amate rial for the coating, it can be connected with the part 20 byvulcanisation for example.

To the ends 21 and 22 adjacent to the gap in the gripping ring 2, twolevers 23 and 24 are connected, respectively, by means of pins 230 and240. The levers 22 and 24 can pivot about pivot pins 231 and 241 locatedintermediately of their ends, and their free ends opposite ring 2 carryrollers 232 and 242. In the rest position shown in FIG. 1, the rollersare caused to abut against each other by a compression spring 25 actingon the lever arms on the side of pivots 231, 241 opposite rollers 232,242. Such roller abutment limits the opening of the gripping ring 2.Above the rollers 232 and 242 a bifurcated lever 3 is provided which canpivot about a pin 30, and a wedge-shaped downwardly inclined projection31 located on the side of pin 30 opposite the lever furcations isarranged directly in front of the rollers 232 and 242. The other,bifurcated, end of the twoarmed lever 3 is connected with a drive part32, which is connected with a rod 33 guided in the housing of thegripping arm 1 and capable of being moved vertically through the rod 33by a solenoid 12. A compression spring 34 encircling the rod 33 andengageable with a collar on the lower rod end reacts against the shellof the gripping arm 1 to press the rod 33 and the drive part 32 normallydownward thereby holding wedge 31 out of engagement with rollers 232 and242. The upper end of the gripping opening or bore of the gripping ring2 is normally closed by a vertically movable plate 4 which is arrangedin the head of the gripping arm 1 and pressed toward ring 2 by a spring40.

n downward movement of the thrust rod 11), the gripping arm is loweredtogether with the centering plate 11 and the gripping ring 2 over thecore or tube of a yarn package, so that the core comes to lie in thebore of the ring 2. The core which comes to extend through the openingof the gripping ring abuts against the abutment plate 4 at the top endof the bore and presses the plate away from the gripping ring 2 againstthe force of the spring 40. Simultaneously the solenoid 12 is actuatedso that the rod 33 is attracted by it and moves upwards together withthe drive part 32 in a vertical direction.

The pivoting movement of the bifurcated lever 3 effected thereby causesthe wedge-like end 31 to be thrust between the rollers 232 and 242 sothat the latter are pushed apart against the force of the spring 25. Thelevers 23 and 24 pivot about the pins 231 and 241 and now exert atension force on the ends 21 and 22 adjacent to the gap in the grippingring 2 so that the ends are moved towards each other. The gripping ring2 is thus caused to contract and becomes pressed against the outerperiphery of the tube 5.

When the core or tube 5 and the yarn thereon has been drawn from thespindle owing to the upward movement of the thrust rod after pivotalmovement of the gripping arm 1, the solenoid 12 is deactivated by aswitch which is not shown in the drawing and the rod 33 is released byit. Accordingly the compression spring 34 is able to press the rod 33with the drive part 32 downwards, so that the latter and the bifurcatedlever 3 with its wedge-shaped end 31 can return into their initialpositions. Owing to the pressing force of the spring 25 the levers 23and 24 swing about the pins 231 and 241 and move the ends 21 and 22adjacent to the interruption in the ring away from each other. The tubeor core 5 is now able to drop out of the opened gripping ring 2.Ejection of the core 5 is aided by the plate 4 which snaps back towardsthe opening of the gripping ring owing to the force exerted by thespring 40.

In the case of the embodiment shown in FIG. 3 the gripping ring consistsof two ring halves or segments 26 and 27, whose adjacent ends 260 and270 are attached at the pivot points 261 and 271 which are stationarywith respect to the housing or shell of the gripping arm.

The levers 23 and 24.are joined in a fixed manner with the opposite ends262 and 272 of the two ring segments 26 and 27, adjacent to the variablegap in the composite ring. The levers 23 and 24 are operated in themanner already explained so that the ring segments 26 and 27 are drawntogether by the tension forces acting at their ends 262 and 272 adjacentto the interruption in the ring and the ring segments accordingly gripthe upper end of the core or tube 5 lying between them.

It is naturally possible for the ends 260 .and 270 to be anchored in amanner different to that shown. Thus, for example, both ends can beanchored at a single point and in this case the ends 260 and 2'70 wouldoverlap or be connected by means of resilient intermediate members.

In another embodiment of the invention the gripping ring or element inaccordance with the invention comprises two superposed interruptedsecondary gripping rings 28, 29 of elastic material arranged so that theinterruptions in them between their respective ends (281, 282 and 291,292) are circumferentially offset (see FIG. 4). The interruptedsecondary rings 28 and 29 are connected with each other by interruptedintermediate rings 28, 29 of non-elastic material in the mannerindicated by connecting lines A. In order to make clear the connectionof the individual secondary rings the superposed secondary rings areshown in exploded relationship in FIG. 4. It will be seen that the end281 adjacent to the interruption of the gripping ring 28 is connectedwith the intermediate ring 28' while the end 282, adjacent to theinterruption, is connected with the intermediate ring 29'. On the otherhand, the end 291 adjacent to the interruption in the ring of the ring29 is connected in a fixed manner with the intermediate ring 29 and theend 292 adjacent to the gap is connected in a fixed manner with theintermediate ring 28. A pressing force acting at the ends adjacent tothe interruptions of the gripping rings 28 and 29 can be produced bymeans of gear wheels (which are not shown) for example. Such gear wheelsare connected respectively with the ends 282 and 292 in a fixed mannerand mesh with a rack which can be moved along the longitudinal axis ofthe gripping arm. If the gear wheels are twisted by means of therespective racks in a direction indicated by the arrows P and P the openends 282, 292 will be moved, owing to the pressing forces acting uponthem, towards the ends 281 and 291, respectively. However,simultaneously, the ends 281 and 291 will be moved towards the ends 282and 292, since the pressing forces engaging the end 282 will betransmitted via the intermediate ring 29' to the end 291 and thepressing forces acting on the end 292 will be transmitted via theintermediate ring 28' to the end 281.

The invention has been described with reference to a travelling copdoffing device. It can, however, also be used successfully withstationarily arranged doffing devices.

We claim:

l. A gripping device for dofi'mg yarn packages wound on tubes on ringspinning and ring twisting machinery comprising an interrupted grippingring engageable with a yarn package tube end portion and having twospaced free ends, and drive means connected with said ends forpositively moving said ends towards each other and thereby contractingsaid gripping ring for pressing it against the outer suface of suchtube, said interrupted with a yarn package tube end portion, saidinterrupted ring comprising a flexible nonelastic annular band and anelastic lining fixed on said band and having two spaced free ends, anddrive means connected with said ends for positively moving said endstowards each other and thereby contracting said gripping ring forpressing it against the outer surface of such tube.

jg ggg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,813,866 Dated June 4, 1974 Inventor(s) Georg Goldammer, Eberhard Grimmand Emil Egli It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Title page; section'75 should read:

--Georg 'Goldammer, Friedrichshofen, West. Germany;

Eberhard Grimm, Ingolstadt, West-Germany; Emil Egli, Windisch,Switzerland-- Signed and sealed this 10th day of December 19%.

(STEAL) Attest:

HcCOY (31830 JR. C, 1*IARt32EMZI, DANE? Arresting Officer Commissionerof Patents

1. A gripping device for doffing yarn packages wound on tubes on ringspinning and ring twisting machinery comprising an interrupted grippingring engageable with a yarn package tube end portion and having twospaced free ends, and drive means connected with said ends forpositively moving said ends towards each other and thereby contractingsaid gripping ring for pressing it against the outer suface of suchtube, said interrupted gripping ring including a plurality of annularinterrupted secondary ring sections, said ring sections being superposedand interconnected and the interruption of each said secondary ringsection being circumferentially offset from the interruptions of theother ring sections.
 2. A gripping device for doffing yarn packageswound on tubes on ring spinning and ring twisting machinery comprisingan interrupted gripping ring engageable with a yarn package tube endportion, said interrupted ring comprising a flexible nonelastic annularband and an elastic lining fixed on said band and having two spaced freeends, and drive meaNs connected with said ends for positively movingsaid ends towards each other and thereby contracting said gripping ringfor pressing it against the outer surface of such tube.